Propeller



' y 3, 1938. J. WEICHWALD 2,116,055

PROPELLER Filed Jan. 17', 1936 WW ATTORNEY.

Patented May 3, 1938 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to propellers and has among its objects to provide a new and useful propeller for aircraft and watercraft which is characterized by a comparatively high propulsive efficiency due to its novel design as clearly set forth in the following specification.

The propeller as shown in the illustrations includes a plurality of blades, preferably two, which are preferably formed integrally with a hub por- 10 tion.

An object of the invention is found in the provision of a propeller having blades the design of which is based on the following features:

(a) The blades or blade portions are preferably 15 formed with an integral hub portion.

(b) The blades or blade portions are designed to evolve from a theoretical line intersecting the longitudinal center line of the drive shaft at a right angle.

20 (c) The thickness of the blades decreases progressively longitudinally of the propeller from the longitudinal axis of the hub portion to the tips of the blade portions.

(CZ) The pitch of each blade evolves from zero at its theoretical center of evolvement on a line of mergence which intersects the longitudinal axis of the hub portion at a right angle thereto. The zero pitch of the blade is shown by Fig. 7 which is a cross-section taken on the zero pitch 30 line 1-1.

(6) The cross-sectional thickness of each blade decreases from the maximum on the longitudinal center line of the blade to the minimum at the leading and trailing edges.

5 (f) The width of the face of each blade decreases from the hub portion to or toward the tip.

With the above and other objects in view, my invention consists in the novel form, construction and arrangement of the propeller parts and ele- 40 ments thereof, shown in preferred embodiment in the attached illustrations, described in the following specifications and particularly pointed out in the appended claims.

Referring to the drawing:

45 Fig. 1 is a view of a propeller embodying my invention looking toward the engine or motor;

Fig. 2 is a side view of same;

Figs. 3, 4 and 5 are cross-sections of the blade of the propeller taken respectively on lines 3-3,

50 4-4 and 55 of Fi 1;

Fig. 6 is a longitudinal section taken on line 6--6 of Fig. 1; and

Fig. 7 is a cross-section taken on the zero pitch line 'I--l of Fig. 1.

55 The propeller as shown in the drawing consists of a pair of blades or blade portions l preferably formed integrally with a hub portion ll.

Any suitable or known means of securing the hub portion to the engine or motor shaft l2 may be employed.

From the illustrations, it will be noted that the propeller includes a design having as a base of evolvement a theoretical line 'l'! which passes transversely of the center of the hub portion and transversely or right-angularly to the longitu- 10 dinal axis X--X of the drive shaft I2.

The pitch of each blade on the axis 'l-'! is zero and each blade has a uniform increase in pitch from zero pitch at the center of the hub portion to its maximum pitch at its outer or tip end.

As shown in Fig. 6, which is a section on the longitudinal center line of the propeller, the thickness of the blade portions decreases progressively longitudinally of the blades from a maximum thickness at the center of the hub portion to a minimum thickness at the tips of the blades.

As. shown in Figs. 3, 4 and 5, the cross-sectional thickness of the blades or blade portion decreases from the maximum on the longitudinal center line of the propeller to a minimum at the leading and trailing edges.

As shown in the illustrations, the width of the face of the blades or blade portions decreases from the hub portion I I to the tips of the propeller.

This application embodies certain matter which has been divided from the showing in Figs. 10 and 11 of my co-pending application Serial No. 759,- 698, filed December 29, 1934, for Propellers.

I claim:

1. A propeller comprising a body having a central hub portion adapted to be secured to a motor shaft and a pair of oppositely disposed blade portions arranged symmetrically about the longitudinal axis of the motor shaft and formed integrally with said hub portion, said blade portions being pitched relatively one to the other oppositely from the center of the hub portion, each blade portion decreasing in face width from a maximum at the center of the hub to a minimum at 5 the tip of the blade, and each blade portion being symmetrical about its longitudinal center line and having a uniform outwardly increase in pitch evolving from zero pitch on a common theoretical line of mergence passing transversely and rightangularly to the longitudinal axis of the motor shaft.

2. A propeller comprising a body having a central hub portion adapted to be secured to a motor shaft and a pair of oppositely disposed blade portions being formed symmetrically about the longitudinal center line of the blades and integrally with said hub portion, said blade portions being pitched relatively one to the other oppositely from the center of the hub portion and so formed that the cross-sectional thickness of each blade portion decreases from a maximum on the longitudinal center line of the blade portion to the minimum at the leading and trailing edges, each blade portion decreasing in face width from a maximum at the center of the hub to a minimum at the tip of the blade, and each blade portion having a uniform outwardly increase in pitch evolving from zero pitch on a common theoretical line of mergence passing transversely and right-angularly to the longitudinal axis of the motor shaft.

3. A propeller blade comprising a hub portion and a blade portion formed integrally with the hub portion, said blade portion having a longitudinal section which decreases in thickness longitudinally of the blade'from a maximum thickness at the center of the hub portion to the minimum thickness at the blade tip, said blade portion being symmetrical about its longitudinal center-line and decreasing in transverse crosssection from the maximum at the longitudinal center line of the blade to the minimum at the edges thereof, the face of the blade portion at its theoretical line of evolvement at the hub center being designed to be disposed transversely and right-angularly to the longitudinal axis of the hub, and the pitch of the blade portion increasing from zero, at said line of evolvement, to the maximum at the blade tip.

4. A propeller comprising a body having a central hub portion adapted to be secured to a motor shaft and a pair of oppositely pitched and oppositely disposed blade portions formed integrally with said hub portion, each blade portion decreasing in face width and thickness longitudinally of the blade from a maximum at the center of the hub to a minimum at the tip of the blade, the blade portions having a uniform outwardly increase in pitch evolving from zero pitch on a common theoretical line of their mergence passing transversely and right-angularly to the longitudinal axis of the hub portion, and the cross-sectional thickness of each blade portion decreasing from a maximum on the longitudinal center line of the blade portion to the minimum at the leading and trailing edges.

JOHN WEICHWALD. 

